Because of the risk of side effects, your GP will prescribe the lowest possible dose of corticosteroids that will control your symptoms.

In some cases, it may take a while to find a dose high enough to control your symptoms but low enough to prevent some or all of the unpleasant side effects.

Read more about the side effects of corticosteroids.

If you have troublesome side effects after taking corticosteroids, do not stop taking your medication until your GP says it is safe to do so. If you suddenly stop taking your medication, you could become very ill.

Length of treatment

If you have to take corticosteroid tablets (oral corticosteroids) for more than three weeks, or you have taken repeated courses over the past few months, you will probably have withdrawal symptoms if you suddenly stop taking the tablets.

Once your symptoms are under control, it is usually recommended your dosage is gradually reduced over a few weeks or months before you stop altogether.

Corticosteroid inhalers and sprays can usually be used on a long-term basis without causing any adverse side effects, apart from an increased vulnerability to developing a fungal infection in the mouth (oral thrush).

Corticosteroid injections can usually be given once every three to six months. More frequent injections are not usually recommended because they can damage tissue. Also, if your symptoms do not respond to infrequent corticosteroid injections, it is likely that alternative treatments will offer a greater chance of success.

Ideally, a course of oral corticosteroids should not last for more than three weeks. After this time, a person is more likely to develop troublesome side effects and withdrawal symptoms. However, a moderate to long-term course of oral corticosteroids is often the only effective form of treatment available.

Corticosteroids work by blocking the effects of a number of chemicals the immune system uses to “kick-start” the process of inflammation.

They can also disrupt the normal functions of white blood cells, which the immune system uses to target and destroy viruses and bacteria.

However, the disadvantage of corticosteroids is that they make you more vulnerable to infection.

Read more about the side effects of corticosteroids.

Inflammation

If part of your body becomes infected, your immune system (the body’s natural defence against infection and illness) responds by flooding the area with infection-fighting antibodies.

The antibodies limit the spread of infection and kill off the virus, bacteria or fungus responsible. However, in the process, the affected area will become swollen, warm and, in the case of the skin, red. This is known as inflammation.

Inflammation is useful in helping prevent the spread of infection. However, sometimes the immune system malfunctions, causing inflammation even though no infection has occurred. This is what happens in conditions such as rheumatoid arthritis, which are known as autoimmune conditions.

Alternatively, the immune system may mistake harmless substances, such as pollen or dust mites, for a threat and trigger an allergic reaction.

Types of corticosteroid

Some commonly prescribed types of corticosteroid include:

• hydrocortisone – usually used as a cream or lotion, hydrocortisone injections are sometimes used to relieve inflammation in joints and tendons
• prednisolone – available as a tablet, injection or as a suppository (a tablet you insert in to your back passage), prednisolone is used to treat a wide range of autoimmune and allergic conditions
• dexamethasone – usually given by injection, dexamethasone is often used when there is an urgent need for treatment, such as when there is swelling in the brain due to a brain tumour or someone is having serious breathing problems due to an allergic condition
• fludrocortisone – this type of corticosteroid is mainly used to treat Addison’s disease, a condition where the body does not produce enough naturally occurring steroid hormones

Corticosteroids, more often known as steroids, are an anti-inflammatory medicine prescribed for a wide range of conditions.

Corticosteroids are available in different forms including:

• tablets (oral steroids)
• injections – which can be into blood vessels, joints or muscles
• inhalers, such as mouth or nasal sprays
• lotions, gels or creams (topical steroids)

This section is about oral, inhaled and injected corticosteroids.

Read more about topical corticosteroids (steroid lotions, gels and creams).

What are corticosteroids used for?

Corticosteroids are mainly used to relieve inflammation. Inflammation occurs when the immune system (the body’s natural defence against infection and illness) causes part of the body to become swollen, red and filled with fluid in response to an infection.

Inflammation is helpful in preventing the spread of infection. However, in some health conditions the immune system triggers inflammation even though no infection is present. These are known as autoimmune conditions and include:

• rheumatoid arthritis – where the immune system causes the joints to become inflamed
• lupus – where inflammation can occur in both the joints and the skin

Sometimes, the immune system reacts to harmless substances (such as pollen), which happens when people have allergic conditions such as asthma.

Inflammation is potentially dangerous if it occurs in the lungs or airways. Corticosteroids are routinely used to treat severe flare-ups of asthma and chronic obstructive pulmonary disease (COPD).

Read more about the uses of corticosteroids and how corticosteroids work.

Side effects

Corticosteroid tablets can cause troublesome side effects if they are taken on a long-term basis. Therefore, they are usually only recommended when a person has a particularly severe flare-up of symptoms.

However, in some circumstances, a long-term course of corticosteroid tablets is the only effective form of treatment. If they are taken for more than three weeks, corticosteroid tablets can cause a range of side effects such as:

• increased appetite that often leads to weight gain
• acne – a long-term skin condition that affects most people at some point
• stomach ulcer – an open sore that can develop on the inside lining of the stomach (a gastric ulcer) or in the small intestine (a duodenal ulcer)
• muscle weakness
• increased risk of infection

A particular concern for people who take corticosteroid tablets over a prolonged period is that they can have an increased risk of developing:

• diabetes – a long-term condition caused by too much glucose (sugar) in the blood
• high blood pressure 
• osteoporosis – weak and brittle bones, which particularly affects people who are 65 or over

Read more about the side effects of corticosteroids.

Corticosteroids can also interact with some other types of medicine, which may alter their effect.

Read more about how corticosteroids interact with other medications.

Pregnancy and breastfeeding

Corticosteroids are generally safe to use in pregnancy. However, they are not usually recommended unless the potential benefits of treatment outweigh any risk to the baby.

For example, oral corticosteroids may be recommended because some conditions, such as severe asthma, may pose a bigger risk than the medication itself.

If oral corticosteroids are required during breastfeeding, prednisolone is usually recommended. This is because it is thought to have the least chance of causing the baby any adverse effects. However, as a precaution, it is recommended you wait for three to four hours after taking a tablet before feeding your baby.

Corticosteroid injections, inhalers or sprays are not thought to pose a threat to babies being breastfed. However, as a precaution, they should only be used if the benefits to the mother outweigh any potential risk.

Read more about who can use corticosteroids.

Corticosteroids can interact with other medicines and the effects of one of the medicines can be altered. This is known as drug-drug interaction.

There is less chance of interaction with corticosteroid injections or sprays, although they can occasionally occur.

Interactions with other medicines

Some of the more common interactions are listed below, but this is not a complete list. If you want to check your medicines are safe to take with corticosteroids, ask your GP or pharmacist, or read the patient information leaflet that comes with your medicine.

Anticoagulant medicines

Anticoagulant medicines are medications that make the blood less sticky. They are often prescribed to people with a history of blood clots or an increased risk of developing them.

Combining corticosteroids with anticoagulant medicines can sometimes make anticoagulants less effective. Alternatively, it can increase their blood-thinning effect, which can cause bleeding inside the digestive system.

Anticonvulsants

Anticonvulsants are medicines used to prevent seizures (fits) and are often used to treat epilepsy. However, they can reduce the effectiveness of corticosteroids. Depending on how frequent and severe your seizures are and the condition that the corticosteroids are being used to treat, your course of anticonvulsants may be temporarily withdrawn.

Anti-diabetes medication

Corticosteroids, particularly steroid tablets (oral corticosteroids), can decrease the effectiveness of medications used to treat diabetes. If you need to take both medications, it is recommended that your blood glucose levels are regularly checked because your dosage of anti-diabetic medication may need to be adjusted.

Antiretroviral medication

Inhaled or intranasal corticosteroids can interact with a type of antiretroviral medication known as protease inhibitors. For example, ritonavir, used to treat HIV and AIDS.

This could lead to side effects such as Cushing’s syndrome, high blood pressure and osteoporosis.

Bronchodilators 

Bronchodilators are medicines that open up the small airways of the lungs (bronchi) to make breathing easier. They are often used to treat conditions that can cause the airways to become narrow or inflamed such as:

• asthma 
• bronchiectasis – a lung condition where the airways are abnormally widened
• chronic obstructive pulmonary disease (COPD) – permanent damage to the lungs usually caused by smoking

Combining corticosteroids and bronchodilators can sometimes cause a fall in levels of potassium in the body. This can lead to abnormal heart rhythms. If you need to take both types of medication, regular blood tests to measure your potassium levels may be recommended.

Live vaccines

Some vaccinations contain a weakened form of the infection they are designed to protect against. These are known as live vaccines. Examples of live vaccines include:

• measles, mumps and rubella (MMR) vaccine
• bacillus Calmette-Guérin (bCG) vaccine for tuberculosis

Due to the immune-weakening effects of corticosteroids, you should postpone any vaccination with a live vaccine for at least thee months after your course of corticosteroids has finished.

Non-steroidal anti-inflammatory drugs

Non-steroidal anti-inflammatory drugs (NSAIDs) are a group of commonly used painkillers, such as ibuprofen, that are available over the counter at pharmacists.

Combining NSAIDs and corticosteroids can increase your risk of developing stomach ulcers and internal bleeding. Depending on other risk factors, you may be given an additional medication called a proton pump inhibitor (PPI). PPIs help reduce the production of stomach acids, which can lower the risk of ulcers forming.

Hormones are powerful chemicals that affect many different processes in the body, from the strength of your bones to your weight. As corticosteroids are hormones, they can have a wide range of side effects.

If you are prescribed corticosteroids, any side effects and their severity will depend on three factors:

• the type of corticosteroid medicine you’re taking – steroid tablets (oral corticosteroids) are more likely to cause side effects than inhalers or injections
• the strength of the dosage – the higher the dose, the greater the risk of developing side effects
• the length of time you are using it for – for example, it is highly likely you will develop more serious side effects if you take oral corticosteroids for more than three months or if you have three to four courses of treatment a year

Inhaled corticosteroids

If inhaled corticosteroids are taken for a short period, most people tolerate them well and have few or no side effects.

Long-term use to treat a condition such as asthma can cause oral thrush. This is a fungal infection that develops inside your mouth.

Rinsing your mouth out with water after using inhaled corticosteroids can help prevent oral thrush.

Injected corticosteroids

Corticosteroids that are injected into muscles and joints may cause some pain and swelling at the site of the injection. However, this should pass within a few days. Over time, repeated steroid injections into a muscle can weaken it.

Corticosteroids are usually only injected directly into the blood when there is an urgent need for treatment. Corticosteroids injected into the blood can cause side effects including:

• stomach irritation, such as indigestion
• rapid heartbeat (tachycardia)
• nausea
• insomnia
• a metallic taste in the mouth

You may also experience mood changes. For example, you could go from feeling very happy one minute to being irritable, depressed or restless the next.

Oral corticosteroids

Side effects of oral corticosteroids used for short periods include:

• increased appetite that often leads to weight gain
• acne – a skin condition that affects most people at some point
• mood changes, such as becoming aggressive, irritable and short tempered with people
• rapid mood swings, such as feeling very happy one minute and very sad and weepy the next

Side effects of oral corticosteroids used for longer than three months include:

• further weight gain
• thinning skin which can bruise easily
• muscle weakness
• a combination of fatty deposits that develop in the face (moon face), stretch marks across the body and acne – this is known as Cushing’s syndrome
• weakening of the bones (osteoporosis)
• the onset of diabetes, or worsening of existing diabetes
• high blood pressure
• glaucoma – an eye condition where fluid gathers inside the eye
• cataracts – an eye condition where cloudy patches develop at the front of the eye
• delayed wound healing
• reduced growth in children
• increased risk of infection

These side effects should improve if you’re able to reduce your dosage. 

However, osteoporosis can be a persistent problem, particularly if you are over 65. This can make you more vulnerable to breaking a bone.

Your GP can prescribe medication and calcium and vitamin D supplements, which help strengthen your bones and can compensate for the effects of prednisolone. Find out more information about treatment for osteoporosis.

You may also be referred for a type of X-ray called a dual energy X-ray absorptiometry (DEXA) scan. This can be used to assess how strong your bones are. You may require several DEXA scans during the course of your treatment. See diagnosing osteoporosis for more information.

Stomach ulcers can be another problem for people who take high doses of oral corticosteroids on a long-term basis. To protect against stomach ulcers, you may be prescribed a type of medication called a proton pump inhibitor (PPI). This reduces the amount of acid in your stomach, which will make you less vulnerable to developing stomach ulcers. Find out more about treating stomach ulcers.

You will also probably have regular checks and tests for conditions such as diabetes, high blood pressure and glaucoma if you need to take oral corticosteroids on a long-term basis.

Mental heath

About 1 person in 20 who takes the oral corticosteroid prednisolone experiences changes in their mental state. These changes may include:

• feeling depressed and suicidal
• feeling manic (very happy and full of energy and ideas)
• feeling very anxious
• feeling very confused
• hallucinations (seeing or hearing things that are not really there)
• having strange and frightening thoughts

If you experience any of these, contact your GP as soon as possible.

Vulnerability to infection

Oral corticosteroids will make you more vulnerable to infection, particularly the viruses that cause:

• chickenpox and shingles (the varicella-zoster virus)
• measles (caused by the paramyxovirus)

You may become very ill if you develop these viral infections, even if you have been previously infected.

Avoid close contact with anyone who has a chickenpox, shingles or measles infection.

Seek medical advice immediately if you think you have been exposed to an infection that causes chickenpox, shingles or measles or if a member of your household develops one of these infections.

Corticosteroids are widely used medications with several uses. 

They are commonly prescribed to:

• help reduce inflammation (anti-inflammatory)
• suppress the immune system (immunosuppressant)
• replace hormones that are not being produced by the body due to a health condition (replacement therapy)

These are discussed in more detail below.

Anti-inflammatory uses

Inflammation occurs when the immune system tries to prevent an infection from spreading. The immune system is the body’s natural defence against infection and illness. It sends special chemicals to the site of the infection, causing it to become inflamed and swollen.

However, in allergic reactions, the immune system regards harmless substances, such as pollen, as harmful. This triggers inflammation. Corticosteroids can help treat a range of allergic conditions, including asthma and allergic rhinitis (hay fever).

These are usually treated using inhalers, although a short course of corticosteroid tablets may be recommended if you have a particularly severe flare-up of symptoms.

Corticosteroids are also used to treat a number of allergic skin conditions, such as:

• urticaria – commonly known as nettle rash
• atopic eczema – which mostly affects children

Corticosteroid creams and lotions are often used to treat these types of skin conditions, although steroid tablets may be needed if your symptoms are particularly severe.

Short courses of corticosteroid tablets are sometimes used to treat people with chronic obstructive pulmonary disease (COPD). COPD refers to a collection of lung conditions that cause breathing problems.

Some people with COPD have periods where their lungs and airways become very inflamed, often as a result of infection. Corticosteroid tablets are routinely prescribed to help reduce the inflammation and improve breathing.

Sometimes, joints, muscles and tendons can become persistently inflamed as a result of injury or over-use. In such cases, a corticosteroid injection may be recommended to help reduce the inflammation.

The immune system

In some illnesses, the immune system malfunctions and attacks healthy tissue. These are known as autoimmune conditions. Corticosteroids can be used to help treat a range of autoimmune conditions including:

• rheumatoid arthritis – the immune system attacks the joints
• lupus – the immune system attacks the skin and the joints
• Crohn’s disease – the immune system attacks the digestive system
• ulcerative colitis – the immune system attacks the colon
• giant cell arteritis – the immune system attacks the arteries
• polymyalgia rheumatica – the immune system attacks the muscles, particularly in the neck and shoulders
• multiple sclerosis – the immune system attacks the nerves

Replacement therapy

Corticosteroids are similar to the natural hormones produced by the adrenal gland (located above the kidneys). These hormones play an important role in regulating the body’s metabolism (the process of converting food into energy).

Corticosteroids are often used to treat Addison’s disease. This is where the adrenal glands do not produce the correct amount of hormones.

Due to their strength, restrictions about who can safely take oral corticosteroids are tighter than those for other types of corticosteroid.

Oral corticosteroids

Oral corticosteroids, also known as steroid tablets, are the most powerful type of steroid medication because they can affect the whole body. Corticosteroids given by injection or inhaler usually affect a specific area of the body.

Someone with an active infection should not start using oral corticosteroids because they could make the infection more severe. However, someone who develops an infection while already being treated should continue to take corticosteroids. Suddenly stopping medication could make them very ill.

Oral corticosteroids may also not be suitable if you:

• have had severe liver disease – they could damage your liver further
• have mental health or behavioural problems, such as depression or alcohol dependence – corticosteroids can have unpredictable effects on behaviour and mood
• have a wound – oral corticosteroids can delay wound healing

If you have any of these, you will probably only be prescribed oral corticosteroids if the benefits of treatment clearly outweigh any potential risks.

Several health conditions can be made worse by taking oral corticosteroids, including:

• heart failure
• a recent heart attack
• high blood pressure 
• type 1 diabetes and type 2 diabetes
• epilepsy
• glaucoma
• underactive thyroid gland
• osteoporosis
• obesity
• psychosis
• stomach ulcers

If you have been diagnosed with any of the above conditions, you will probably only be prescribed oral corticosteroids if the benefits of treatment clearly outweigh any potential risks.

Corticosteroid injections

Most people can safely have corticosteroid injections, also known as intravenous corticosteroids.

However, intravenous corticosteroids are not recommended for people with an active infection, unless they have a potentially life-threatening condition that requires urgent treatment.

Inhalers and sprays

Corticosteroid inhalers and sprays are generally safe for most people to use. However, you should not use them if you have ever had an allergic reaction to the ingredients in them.

Pregnancy

Corticosteroids are generally safe to use during pregnancy. However, they are not usually recommended unless the potential benefits of treatment outweigh any potential risk to the baby.

For example, oral corticosteroids may be recommended because some conditions, such as severe asthma, may pose a bigger risk than the medication itself.

The benefits of using inhaled corticosteroids during pregnancy for conditions such as asthma are thought to far outweigh any potential risk.

There is no evidence that a single injection of corticosteroids during pregnancy poses any threat to the baby, although repeated injections may cause low birth weight.

Breastfeeding

If oral corticosteroids are required during breastfeeding, prednisolone is usually recommended because it is thought to have the least chance of causing the baby any adverse effects. However, as a precaution, it is recommended that you wait three to four hours after taking a tablet before feeding your baby.

Corticosteroid injections, inhalers or sprays are not thought to pose a threat to babies being breastfed. However, as a precaution, they should only be used if the benefits to the mother outweigh any potential risk.